Control of electrically-operated switches.



H. E. WHITE. 4 CONTROL OF ELEGTRICALLY OPERATED SWITCHES.

APPLICATION FILED JULY 19, 1910.

WITNESSES.- INYENTUH E AHULD I! WHITE.

firs 4T THEME}? 1,025,498. Patented May 7, 1912;

" UNITED STATES PATENT OFFICE.

HAROLD E. WHITE, OF SCHENECTADY, NEW YORK, .ASSIGNOR TO GENERAL-ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

CONTROL OF ELECTRICALLY-OPERATER SWITCHES.

Specification of Letters Patent.

Patented May 7, 1912.

Application filed July 19, 1910.- Serial No. 572,714.

To all whom it may concern:

Be it known that I, HAROLD E. WHITE, a citizen of the United States, residing at Schenectady, count of Schenectady, State of New York, have ln-vented certain new'and useful Improvements in the Control of Electrically-Operated' Switches, of which the following is a specification.

My invention relates tothe control of electrically operated switches, and particularly to the control of a plurality of such switches or contactors which are intended to r be operated in succession. A plurality of successively operating contactors are often employed in the control of electric motors and my invention is particularly adapted for use in this connection.

It is a general object of my invention to provide a new and improved control system for a plurality of contactors of the type in which the successive operation of said contactors takes place automatically and, if desired, under the control of means responsive to the conditions in the motor circuit.

To the above end, my invention (3011'1- prises a plurality of contactors, auxiliary switches cooperating with certain of said contactors each arranged to control the operation of a succeeding contactor, each auxiliary switch being so connected to its cont-actor that it will be held open while said contactor is open, and each auxiliary switch being provided with, a magnet adapted to control its closing; means being provided for energizing and deenergizing these magnets successively, the energization of each magnet being substantially coincident with the deenergization of the magnet of the auxiliary switch of the preceding contactor. In connection with the above elements, I also prefer to use means responsive to the conditions in the power circuit to be controlled for controlling the operation of the means which causes the energization and deenergization of the auxiliary switch magnets.

My invention will be understood from the following description of one embodiment thereof taken in connection with the accompanying drawing, in which the system is diagrammatically illustrated in connection wit-h anautomatic star-ting system for an induction motor.

It is, of course, to be understood that my invention may be used in connection with many kinds of motor control systems, both for alternating and for direct current operation.

Referring to the drawing, the motor to be controlled is shown at M as an induction motor provided with slip rings which permit external resistance rotor circuits. It is this resistance, which is made up of the contactors 1 to 5, short circuit in closing. these. contactors being the ones to which my invention is applied. The source of alternating current for the motor is indicated at L. In the particular system shown the source of current for the control circuits of the cont-actors is'indicate'd at Z, this source furnishing either direct or alternating current, depending upon the kind for which the contactors and other control apparatus are designed. It will be apparent from the diagram that the contactors 1 and 2 short circuit the sections of resistance R, R and R and that the contactors 3, 4 and 5 short circuit the sect-ions of resistance R R and R. As to their mechanical construction, these contactors may be of the type shown in the co-pending application filed by me jointly with E. R. Carichoff, Serial No. 480,483 filed February 27, 1909, and in the application filed by me Serial No. 480,481 filed February 27, 1909. Of these contactors, c011 tactors 1 to 4 are characterized by the fact that they areeach provided with an auxiliary switch which is mechanically so connected tothe movable member of the contactor that said auxiliary switch is held open while the cont-actor is open and is controlled in closing only by a magnet which cooperates with said auxiliary switch. In the drawing, referring to the contactor 1, the movable contact member is indicated at 10 cooperating'with the fixed contact member 11, said movable contact member 10 being connected to a core 12 of magnetic material which is acted upon by an actuating to be used in the is mechanically similar. to the tact-or is open magnet coil 13. The auxiliary switch cooperating with this contactor is shown as having fixed contacts 14: with which the contact disk 15 coiiperates, this disk being carried by a vertically movable rod 16 which at its upper end coiiperatesat 17 with the heel of the movable contact member 10, the arrangement beingsuch that when the conthe rod 16 and disk 15 are held'in the position shown and when the contactor is closed the rod 16 is released. The rod 16 carries a core 18 of ma etic material which moves within the fiel magnet coil which is so designed and arranged that when it is energized it will hold said core in its u per position and thereby maintain the dis 15 out of engagement with the contacts 1% even after the contactor has closed and the rod 16 has .been released.

At 20 is shown a dummy contactor, (that is, one which has no main contacts,) which cont-actors 1 to a and is provided with an auxiliary switch similar to those coiiperating with the contactors 1 to 4:- This dummy cont actor is held in, after it is'once closed, in any desired way, as, for instance, by establishing a holding circuit through the contact 20' at the upper end of the core ot the contact/r. Inspection of the-control circuits will show that the actuating coils of the contactors 1 toare respectively controlled by the auxiliary switches cotiperating with the preceding contactors and 1 to at. lit will also be noticed that the magnetic coils 22, 23 and 24: of the auxiliary switches coiiperating with the contactors 20,2 and 4: are connected in series and that the magnet coils 25 and 26 of the auxiliary switches coiiperating with contactors 1 and 3 are connected in series.

The auxiliary switches are so constructed that their magnetic windings 22 to26 act as the circuits through holding coils only and will not lift their re spective cores. lin other words, the coils 22, 23 and 24: being connectedin series are only strong enough 'to hold up their cores after they have been mechanically lifted. This is likewise true of coils 25 and 26.

At Q is diagrammatically represented a notching device which alternately energizes the magnet coils 22, 23 and 24 and through 26. This device Q, may be of any suitable form and, as shown, comprisesa switch member having se ments 30, 31, 32 and 33 which are engage by a rotatable. arm 34 carried by a shaft 35 which is rotated through angles of 90 by a magnetically recipro ited device. This device com rises a magnet 37 which acts u on a vertical y movable core 38 biased to t e position shown by a spring 39, this core 38 having connected to it a pawl 40 which engages with the teeth eta .mar" leads of the motor.

this relayv O are located in. the circuit the magnet coils 25 and actuating coil 0 acetates of a ratchet wheel 4:1, in the manner clear from the drawing. The core 38 in its uppermost position coiiperates with a rod 42 carrying the contact disk 43 .which, core is down, bridges fixed contacts 44 located in the circuit of the magnet 37. With this arrangement, when the circuit through the magnet 37 is completed, the core 38 is pulled up and in its upper position said core,

when the through the medium of the rod 42, lifts the disk 43, thereby openingthe circuit-of the magnet 37 and permitting the core 38 to return to its lower position under the influence of the spring 39, after which the disk 43 falls and the magnet 37 is again energized. The segments 30 and 32 of the electrically connected to the wire 47 leading to the magnets 25 and 31 and 33 are connected to the wire 48 leading to the magnets 22, 23 and 2A. The contact arm 34 is connected to a wire 49 which is connected to the-positive side of the source Z through the contacts oi the no voltage relay P, the coil of which is connected across two of the leads from the source lb to the primary of the motor M. This relay P, the contacts of which are open when its actuating coil is deenergized, is retarded in its closing movement by the dashpot50, which, however, does not impede the opening of the relay contacts when the actuating coil. is deenergized.- The action of the dash-pot 50 is 1 indicated by the valve in its piston, in the usual conventional manner. a relay which is made responsive to the conditions in the motor circuit by having its coil connected in series with one of the pri- The contacts of through the magnet 37 of the notching device Q and this relay serves to stop the operation of said notching device upon the occurrence of an overload on the motor. The-ac tion of the device Q is also stopped after all the contacts have closed by the opening of an auxiliary switch 52 located in the cirdevice Q are 26, and thesegments' At U is shown cuit of the magnet 37 and opened by the contactor 5 in closing.- Tnspection of the dia- I gram will also show. that one side of the actuating coilsflof the contactors 1 to' 5 is connected to a wire 53 which leads to the positive side of the source I through the contacts of the i'relay' P; that one side of the the contactor 20 is con-- nected through wire 54 to the wire 48; that the other end of the actuating coil of the contactor 20 is connected to the return wire. 55 leading to the negative side of the source Z through the wire 56, while the other ends of the actuating coils of the contactors 1 to 5 are, respectively, connected through the auxiliaryswitches'of the contactors 20 and.

- 1 to 4 to the'return wire55; and that the two circuits through wire 47 and magnets 25 and 26' and through wire cuit established at the contact 20 24 are connected to ther at 57 and to the return wire 56 leading to the negative side of the source l. A main starting switch, which completes the motor circuit and starts the automatic 0 eration of the contactors, is indicated at Of course, if desired,

other starting switches may be employed both in the primary circuits of the motor and in the control clrcuits, as will be understood by those skilled in this art.-

The operation of the system shown in the diagram is as follows: is closed, the primary circuits of the motor are connected to the source L and the motor will begin to operate with all the resistance R to R in its rotor circuits. The actuating coil of the relay P will be energized as soon as the switch W is closed and said relay will commence to move to its closed position, being retarded in its operation by the dashpot 50. The interval the relay P to close will be sutficient to allow the overload relay 0 to open its contacts if the current in the primary circuit of the motor exceeds a safe value while the motor is starting. As long as the contacts of the relay O are open the notching device Q will be inoperative. As soon, however, as the relay O closes its contacts the magnet 37 will be energized and the device Q will commence operating and will connect the wires 47 and 48 alternately to the wire leading to the positive side of the source Z through the contacts of the relay P. If the device Q happens to be in the osition shown when the switch W is closed the wire 48 will be energized immediately from the positive side of the source Z, through the contacts of relay P, wire 49, contact arm 34, and segment 33, whereupon the dummy contactor 20 will be actuated and a maintaining cir- Wire 53. The auxiliary switch cooperating with this contactor will, however, not close because its magnet 22 will be energized.

from the wire 48 and will, therefore, hold said auxiliary switch open, thereby preventing the completion of the circuit through the actuating coil of the contactor 1. Until, therefore, the relay 0 has closed its contacts and the notching device Q has operated the contact arm 34 through 90, no resistance will be cut out of the rotor circuit of the motorhad happened tov If the notching device Q be, when the switch W was closed, 1n one of the ositions in which the wire 47 is energized not even the dummy contactor 20 would have operated.

parent that under no conditions can any of the resistance controlling contactors 1 to 5 close immediately upon the closin of the switch W, or upon the consequent c osing of the contacts of the relay P, and none of said 48 andmagnets 22 and When the switch W' of time which it takes through It is, therefore, ap-v contactors will close thereafter unless the current in the stator circuit of the motor is insufficient to cause the overload relay 0 to open its contacts. As long, however, as the contacts of the relay 0 are closed, the notch ing device Q will continue to operate and by rotating the contact arm 37 Wlll alternately energize and denergize the wires 47 and 48 leading, respectively, tothe magnets 25 and 26 and the magnets 22, 23 and 24 with consequent successive operation of the contactors now to be descri ed. Starting with the notching device Q in the position shown, after the contact arm 34 has moved 90 the wire 48 and therefore the magnet 22 will be denergized, thereby allowing the auxiliary switch of the contactor 20 to close and thereby completin the circuit through the actualting coil of the contactor -1, which will 0 ose. the movable member of its auxiliary switch but said switch will not close because sub stantially coincidently with the denergization of the wire 48, the wire 47 and therefore the coil 25 was energized. When the notching device Q has turned the arm 34 another 90 are denergized, and the auxiliary switch controlled by this magnet is allowed to close, thereby causing closing of the contactor 2, the magnet 23 of the auxiliary switch of said contactor being simultaneously ener- 'zed. From the foregoing it will be apparent that further operation of the notching de-' vice Q will cause the contactors 1 to 5 to close automatically in succession, the device Q being in turn limited in its operation by the overload relay 0, which stops the notching device if at any time the current in the primary circuit of the motor exceeds a safe value. Closing of the contactors I to 5 re- Closing of the contactor 1 releases the wire 47 and the magnet 25 I sults in cutting out the resistance-R to R 7 1n the circuits of the rotor of the motor, thereby increasing the speed of the latter in a well-known manner.

It will be obvious to those skilled in this art that my invention may be modified in many respects without departing from its spirit, and it is my intention to cover all such arrangements in the claims hereto appended. I

What I claim as new and desire to secure by Letters Patent of the United, States is,

In'combination with a power circuit, a plurality of contactors intended for operation in succession to efl'ect certain connections in said power circuit, auxiliary switches cooperating with certain of; said contactors each arranged to controlthe operation of a succeeding contactor, means for positively holding each auxiliary switch open while its cooperating contactor-is open, magnets each cooperating with an auxiliary I with the "magnets each cooperatinglwith an auxiliary cuits 7 alternately the switch for controlling the switches, the energization of each magnet being substantially coincident with the deof the auxiliary.

energization of the magnet switch of the preceding contactor v 2. In combination with a power circuit,

a plurality of contactors intendedtor. operation in succession to efiect certain connections in said power circuit, auxiliary switches cooperating with certain of said contactors each arranged to control the op-- nets of alternate contact'ors are connected,

a circuit to which the auxiliary switch magnets of the other contactors are connected,

and means for energizing and deenergizingsaid circuits alternately the energization of place substantially coincidently one taking e'energization of the other.

' 3. In combination with a power-circuit, .a

plurality or contactors intended for opera tion in succession to efiect certain connections in said ower circuit, auxiliary switches cooperating with certain of said.

contactorseach arranged to control the operation of a succeeding contactor, means for positively holding each auxiliary switch open while its cooperating contactor is open, switch for controlling t e closing thereof, means for energizing cessively the magnets of said auxiliary switches the energization of each magnet being suhstantially coincident withthe denergizatlon of the magnet of the auxiliary.

switch of the preceding contactor, and

means responsive to the conditions in said power circuit for controlling the operation:

of said last mentioned means.

4. In combination witha power circuit, a plurality of contactors intended for'opera- -t1on in succession to efiect certain connections 1n said circuit'to which the auxiliary switch magnets .of alternate contactors are connected, a circuit to which the auxiliary switch magnets of the other contactors are connected, means for energizing and deenergizing said cirenergization of one 7 taking place substantially coincidently with closing thereof, and means for energizing and deenergixing; successively the magnets of said auxiliary cooperating contactor is open, cooperating with an auxiliary v tions and. delnergizing suc- I "place substantially coincidentlg energization of relay responsive ower circuit, auxiliary switches cooperating with certain of said contactors each arranged to control the options cooperating with an auxiliary switch for controlling the closing thereof, a

' magnets each cooperating the denergization of the other, and means responsive to the conditions in said power circuit for controlling the operation ofsaid last mentioned means.

5. combination with a power. circuit, a plurality or contactors intended for operation in succession to efiect certain connections in said power circuit, auxiliary switches cooperating with certain of said contactors each arranged-to control the o succeeding contactor, means or positively holding each auxiliary switch open while its coiiperating contactor is open, magnets each cooperating with an auxiliary switch for controlling the closing thereof, a circuit to which the auxiliary switch magnets of alter- I note contactors are connected, a circuit to which the auxiliary switch magnets of the other contactors are connected, and a magnetically operated notching device for energizing and deenergizing said circuits alternately, the energization of one taking place substantially coincidently with the deenergization of the other.

6, In combination witha a plurality of contactors intcn ed for operation in succession to efiect certain connecin said power circuit, auxiliary switches coopcratlng with certain of said contactors each arranged to control the operation of a succeeding contactor, means for positively holding each auxiliary switch open while its cooperating contactor is cpen,

mag'netseach cooperatin with an auxiliary switch for controlli g t e closing thereof, a circuit to which th auxiliary switch magnets'of alternate contactors arerconneoted, a

circuit to which the auxiliary switch magnets of the other contactors are connected, a magnetically operated notching device for energizing and dcenergizing said circuits alternately, the energization of one taking the other, an an overload to -the.-conditions in the power circuit for preventing the operation of said notching device during overload conditions in the power circuit. 7. In combination with a: power circuit, a1 plurality of contactors intended for operation in succession to effectcertain connecin' said ower circuit, auxiliary switches cooperating with certain of said contactors each arranged to, control the operation of a succeeding contactor, means for positivelyholding each auxiliary switch open while its cooperatingcontactor is open, with an auxiliary switch for controlling the closing thereof, a circuit tofwhich the auxiliary switch magnets of alternate contactors are connected, a circuit to which the auxiliary switch magnets of the othcr-contactors areconnected a magnetically operated notching device or eration of a,

ower circuit,

with the deenergizing and deenergizing said circuits alslow-010s relay controlling the energizaternately, the energization of one taking vtion of sai alternately energlzed circuits. 10

place substantially coincidently with the de- In witness whereof, I have hereunto. set energization of the other, an overload relay my hand this 18th day of July, 1910. responsive to the conditions in the power HAROLD E. WHITE. circuit for preventing the operation of said Witnesses:

notohing device during overload conditions BENJAMIN B. HULL,

in the power circuit, and a normally open Hnmm ORFORD. 

